David had 20 pencils.5 of them are green and 15 are purple. What percentage of pencils were green?

25%

Step-by-step explanation: Since we know that David has 20 pencils in all and that 5 of the pencils he has are green, we have the fraction 5/20 which represents the 5 green pencils out of all of his pencils.

Now, remember the problem is looking for a percent so we need to write 5/20 as a percent in order to answer the question.

To write a fraction as a percent, first remember that a percent is a ratio of a number to 100. So to write 5/20 as a percent, we need to find a fraction equivalent to 5/20 that has a 100 in the denominator. We can do this by setting up a proportion.

Now, we can use cross products to find the missing value.

So we have 5 times 100 which is 500 is equal to 20 times n or 20n.

So we have 500 = 20n.

Now, dividing both sides of the equation by 20, we have 25 = n.

So 5/20 is equal to 25/100 or 25%.

Therefore, 25% of David's pencils are green.

f

step-by-step explanation:

f

(n^3 - n)

= n(n-1)(n+1)

since it is divisible by 3 and 2 ,because it is a multiple 3 consecutive number

if, n-1 is odd then n+1 is also odd, then it is a multiple of 9

but if, n-1 is even then n+1 is also even, then it is a multiple of 4

so, largest multiple = max(9*2, 4*3) = max(18, 12) = 18